我正在寻找一种使用ZoomIn / ZoomOut功能以全尺寸显示非常大的可滚动图像（3700x2400）的方法。
以下问题给了我一个完美的解决方案： Android imageView Zoom-in and Zoom-Out
package com.oryx.hanenberg;
/**
* Created by Jordy on 9-2-2017.
*/
import android.app.Activity;
import android.graphics.Matrix;
import android.graphics.PointF;
import android.os.Bundle;
import android.util.FloatMath;
import android.util.Log;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnTouchListener;
import android.widget.ImageView;
public class ZoomInZoomOut extends Activity implements OnTouchListener
{
private static final String TAG = "Touch";
@SuppressWarnings("unused")
private static final float MIN_ZOOM = 1f,MAX_ZOOM = 1f;
// These matrices will be used to scale points of the image
Matrix matrix = new Matrix();
Matrix savedMatrix = new Matrix();
// The 3 states (events) which the user is trying to perform
static final int NONE = 0;
static final int DRAG = 1;
static final int ZOOM = 2;
int mode = NONE;
// these PointF objects are used to record the point(s) the user is touching
PointF start = new PointF();
PointF mid = new PointF();
float oldDist = 1f;
private ImageView imageView;
private int fieldImgXY[] = new int[2];
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_map);
imageView = (ImageView) findViewById(R.id.map);
int[] posXY = new int[2];
imageView.getLocationOnScreen(posXY);
int x = posXY[0];
int y = posXY[1];
Log.d(TAG, TAG + " " + String.valueOf(x));
Log.d(TAG, TAG + " " + String.valueOf(y));
imageView.setOnTouchListener(this);
}
@Override
public boolean onTouch(View v, MotionEvent event)
{
ImageView view = (ImageView) v;
view.setScaleType(ImageView.ScaleType.MATRIX);
float scale;
dumpEvent(event);
// Handle touch events here...
switch (event.getAction() & MotionEvent.ACTION_MASK)
{
case MotionEvent.ACTION_DOWN: // first finger down only
savedMatrix.set(matrix);
start.set(event.getX(), event.getY());
Log.d(TAG, "mode=DRAG"); // write to LogCat
mode = DRAG;
break;
case MotionEvent.ACTION_UP: // first finger lifted
System.out.println(event.getX());
System.out.println(event.getY());
break;
case MotionEvent.ACTION_POINTER_UP: // second finger lifted
mode = NONE;
Log.d(TAG, "mode=NONE");
break;
case MotionEvent.ACTION_POINTER_DOWN: // first and second finger down
oldDist = spacing(event);
Log.d(TAG, "oldDist=" + oldDist);
if (oldDist > 5f) {
savedMatrix.set(matrix);
midPoint(mid, event);
mode = ZOOM;
Log.d(TAG, "mode=ZOOM");
}
break;
case MotionEvent.ACTION_MOVE:
if (mode == DRAG)
{
matrix.set(savedMatrix);
matrix.postTranslate(event.getX() - start.x, event.getY() - start.y); // create the transformation in the matrix of points
}
else if (mode == ZOOM)
{
// pinch zooming
float newDist = spacing(event);
Log.d(TAG, "newDist=" + newDist);
if (newDist > 5f)
{
matrix.set(savedMatrix);
scale = newDist / oldDist; // setting the scaling of the
// matrix...if scale > 1 means
// zoom in...if scale < 1 means
// zoom out
matrix.postScale(scale, scale, mid.x, mid.y);
}
}
break;
}
view.setImageMatrix(matrix); // display the transformation on screen
return true; // indicate event was handled
}
/*
* --------------------------------------------------------------------------
* Method: spacing Parameters: MotionEvent Returns: float Description:
* checks the spacing between the two fingers on touch
* ----------------------------------------------------
*/
private float spacing(MotionEvent event)
{
float x = event.getX(0) - event.getX(1);
float y = event.getY(0) - event.getY(1);
return (float) Math.sqrt(x * x + y * y);
}
/*
* --------------------------------------------------------------------------
* Method: midPoint Parameters: PointF object, MotionEvent Returns: void
* Description: calculates the midpoint between the two fingers
* ------------------------------------------------------------
*/
private void midPoint(PointF point, MotionEvent event)
{
float x = event.getX(0) + event.getX(1);
float y = event.getY(0) + event.getY(1);
point.set(x / 2, y / 2);
}
/** Show an event in the LogCat view, for debugging */
private void dumpEvent(MotionEvent event)
{
String names[] = { "DOWN", "UP", "MOVE", "CANCEL", "OUTSIDE","POINTER_DOWN", "POINTER_UP", "7?", "8?", "9?" };
StringBuilder sb = new StringBuilder();
int action = event.getAction();
int actionCode = action & MotionEvent.ACTION_MASK;
sb.append("event ACTION_").append(names[actionCode]);
if (actionCode == MotionEvent.ACTION_POINTER_DOWN || actionCode == MotionEvent.ACTION_POINTER_UP)
{
sb.append("(pid ").append(action >> MotionEvent.ACTION_POINTER_ID_SHIFT);
sb.append(")");
}
sb.append("[");
for (int i = 0; i < event.getPointerCount(); i++)
{
sb.append("#").append(i);
sb.append("(pid ").append(event.getPointerId(i));
sb.append(")=").append((int) event.getX(i));
sb.append(",").append((int) event.getY(i));
if (i + 1 < event.getPointerCount())
sb.append(";");
}
sb.append("]");
Log.d("Touch Events ---------", sb.toString());
}
}
activity_map.xml
<LinearLayout android:orientation="vertical" xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_gravity = "center_vertical|center_horizontal|center"
android:layout_weight="1"
>
<ImageView
android:id="@+id/map"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="@drawable/bt_587f3ef7ccafa_bt_origineel"/>
</LinearLayout>
但是，我希望触摸事件能够记录相对于图像的X / Y坐标。现在，当我缩放产生错误的X / Y坐标时，它会在图像周围创建空白区域。 X / Y坐标也是视口，而不是整个内容。我怎么能做到这一点？
答案 0 :(得分：2)
您可以按照以下说明获取Imageview的左上角：
int[] posXY = new int[2];
imageView.getLocationOnScreen(posXY);
使用此触摸坐标，您可以按如下方式计算ImageView内的点：
int touchX = (int) event.getX();
int touchY = (int) event.getY();
int imageX = touchX - posXY[0]; // posXY[0] is the X coordinate
int imageY = touchY - posXY[1]; // posXY[1] is the y coordinate